Conveying systems utilizing a rotating drive shaft and a contacting drive wheel have been disclosed in the prior art. Typical of such devices are those disclosed in the following U.S. Pat. Nos.: 3,356,040 (Fonden); 3,118,393 (Ohlin); 3,858,626 (Ribordy); and 3,858,707 (Block et al). In all of these patents, the drive wheel is mounted for rotation so that a radial surface of the drive wheel contacts the drive shaft.
While this type of conveying system is workable, a number of disadvantages exist. For example, the longitudinal drive shaft must be rotated at a high speed, such as 320 RPM. In addition, a significant bearing force must be exerted between the radial surface of the drive wheel and the drive shaft in order to cause relative movement. For example, a force of 225 pounds may be necessary. The result of the high speed of rotation and large bearing force is a rapid wearing of the drive wheel.